The simulation began with the Lexington and the Excalibur engaging the Enterprise near the planet Alpha Carinae II in an unscheduled battle to test the M-5's reaction to a surprise attack. After-action analysis, based on the quantity and quality of hits on the Lexington, indicated that the Enterprise, directed by the M-5, had been victorious.

Later, when the M-5 became unstable, the Lexington was hit multiple times by full-powered phasers from the Enterprise in the engineering section, damaging impulse engines and leaving her maneuverable only on warp drive. Fifty-three of her crew were killed.

When the Excalibur's entire crew was killed and she was left adrift by the M-5, Wesley requested and received permission to destroy the Enterprise with the remainder of his damaged ships. However, the M-5 was deactivated before this could be carried out. (TOS: "The Ultimate Computer")